Alkali-soluble surfactant consisting of substituted succinic acid-nonionic ethoxylate blends

ABSTRACT

NONIONIC ETHOXYLATES SURFACTANTS, WHICH ARE KNOWN TO BE VERY DESIRABLE COMPONENTS IN HEAVY DUTY CLEANING PRODUCTS, SUFFER FROM THE FACT THAT THEY HAVE LIMITED SOLUBILITY IN SOLUTION OF ALKALINE ELECTROLYTES AND THUS ARE NOT SOLUBLE OF ALKALINE BUILDER CONCENTRATES. ADDITION OF MODERATE AMOUNTS OF SUBSTITUTED SUCCINIC ACIDS OVERCOMES THIS DEFECT AND PERMITS THE INCLUSION OF THESE NONIONICS IN BUILT LIQUID DETERGENT CONCENTRATES.

3,579,453 Patented May 18, 1971 3,579,453 ALKALI-SOLUBLE SURFACTANTCUNSISTING F SUBSTITUTED SUCCINIC ACID-NONIONIC ETHGXYLATE BLENDS JeanDupre, Levittown, and Harrison Scott Killam, Holland, Pa., assignors toRohm and Haas Company, Philadelphia, Pa. N0 Drawing. Filed Nov. 12,1968, Ser. No. 775,137 Int. Cl. Clld 1/66 US. Cl. 252-89 8 ClaimsABSTRACT OF THE DISCLOSURE Nonionic ethoxylated surfactants, which areknown to be very desirable components in heavy duty cleaning products,sulfer from the fact that they have limited solubility in solutions ofalkaline electrolytes and thus are not soluble in alkaline builderconcentrates. Addition of moderate amounts of substituted succinic acidsovercomes this defect and permits the inclusion of these nonionics inbuilt liquid detergent concentrates.

This invention relates to surfactant compositions which can beincorporated into built liquid detergent concentrates, and at the sametime possess useful performance characteristics in dilute cleaningbaths,

Broadly stated, the invention pertains to surfactant compositions thatare soluble in solutions of alkaline builders having a high solidscontent.

An object of the invention pertains to surfactant compositions that aresoluble in solutions of alkaline builders having a high solids content.

An object of the invention is to provide means for solubilizingpolyethylene oxide containing nonionic surface active compositions intobuilder solutions.

A further object is to provide homogeneous built liquid detergents andalkaline cleaners containing polyethylene oxide nonionic surfactants andalkaline builders, characterized by the possession of low foamingproperties even when used in high pressure automatic cleaningoperations.

Alkaline cleaners are the most widely used means in industry forcleaning meal, glass, certain plastics, etc. In the metal-forming field,in particular, such cleaners are used to remove various types of soilssuch as cutting oils, grinding( buffing, stamping and drawing compounds.The alkaline cleaning solutions may be used in various types of cleaningmethods and apparatus, e.g. soaking, spraying, electrolytic, et al.

Currently, the trend in industrial use of alkaline cleaners is in thedirection of automated operations as a means of reducing manpower andtime requirements. The preferred detergent products for these operationsare aqueous built liquids containing surfactants and high levels ofalkaline builders. The preferred surfactants are the nonionicethoxylated type, for they have some or all of various desirablefeatures such as superior detergent action, rapid wetting, low foamingcapacity, soil defoaming capacity, emulsifying properties, free rinsing,etc.

All nonionic surfactants based on polyethylene oxide units as thehydrophilic portion, however, suffer from a basic deficiency, They havepoor tolerance in solutions for alkaline electrolytes, and thus are notsoluble at the levels of alkaline builders required for a practicalliquid detergent concentrate. It is believed that this is due to thefact that the other oxygen atoms of the polyethoxy chain lose Water ofhydration excessively in alkaline builder solutions. In any event, thenonionic surfactants exhibit a cloud point whereby above thistemperature the surfactant separates into a second phase.

Alkaline builders cause the cloud point to be lowered to a point wherephase separation occurs at ambient temperature. Increasing the number ofethoxy groups in the molecule does raise the cloud point in water or inbuilder solutions of low concentrations, but solubility at high builderlevels cannot be achieved regardless how many ethylene oxide units arepresent. Moreover, to modify the nonionic structure as by incorporatingionic groups may improve alkali tolerance but will also alter theperformance undesirably as well as increase the costs.

A particularly difiicult part of the general problem of incorporatingnonionic ethoxylated surfactants into aqueous alkaline builderconcentrates is that of using lowfoaming nonionic surfactants. Thisgroup of ethoxylates must have relatively low cloud points in dilutesolutions in order to exhibit low foaming properties at usetemperatures. Consequently, they have not heretofore been capable ofbeing incorporated into builder solutions even at relatively lowalkaline builder levels. Nonetheless, low foaming nonionics areespecially desirable for incorporation into built liquid detergentssince many of the automated cleaning machines employ a power washingcycle. Although their greater mechanical action enables power washers togive quicker and better cleaning action than is achieved by stillsoaking and the like, their one big drawback is their tendency togenerate excessive foam, the air content of which reduces the cleanersdensity and mechanical impact. The use of low foaming nonionicsurfactants not only avoids this problem, but also serves to reduce thefoam caused by certain soils such as proteinaceous matter.

The present invention has made it possible to incorporate nonionicpolyethylene oxide type nonionics, such as the well known, commerciallyavailable Triton X-lOO, into alkaline builder solutions. This has beenaccomplished by blending together with those nonionics, in certainratios of one to the other, certain substituted succinic acids. Theeffectiveness of such blends in making soluble in builder solutionsnonionics which heretofore had no such properties is remarkably good.The presence of the substituted succinic acids raises the cloud point ofthe nonionics in the builder solutions to such an extent that clear,homogeneous solutions are obtained at ambient temperatures. Otherhydrotropes are known to have some solubilizing activity for nonionicsin builder solutions, but are unsatisfactory for most industrialapplications because they require either too high a ratio of hydrotropeto nonionic or permit only such a relatively low concentration ofbuilder as to make the resulting products have too little economicutility.

Another advantage derived from our novel utilization of the substitutedsuccinic acids as part of the surfactant compositions of the presentinvention resides in the surprising fact that, unlike other hydrotropes,they do not adversely affect the properties or performancecharacteristics of the nonionics in the end-use baths. This particularcharacteristic is extremely important in power washing operationsbecause any significant contribution of foam by the hydrotrope wouldmake those materials useless.

The compositions of the present invention, which so effectively combinethe property of solubility in highly built liquids with the performanceproperties of ethoxylated nonionics, essentially consist of blends ofthe following constituents:

25-90% of a substituted succinic acid,

R is an alkyl or alkenyl group, branched or straight chain, of 7 to 12carbon atoms, and

-75% of a nonionic polyethoxylated surfactant. Illustrative of thenonionic surfactants which may be employed are those from the groupconsisting of;

R CHzO-O R where R is an alkoxy group whose alkyl portion has 818Catoms, an alkyl amine whose alkyl portion has 818 C atoms, or an alkylphenoxy group whose alkyl portion has 6 to 12 C atoms,

R is H, a C alkyl group, benzyl, acetate, ethyl acetyl,

acetal, or chloro group,

R2 is H, CH3, or C2H5, and

(2) Ethylene oxide-propylene oxide block copolymer. A preferred novelblend in accordance with the present invention is one in which thesubstituted succinic acid is the n-octenyl adduct, the nonionicpolyethoxylate is a low-foaming polypropylene oxide terminatedethoxylated linear primary alcohol, and the ratio of the former to thelatter varies between 1.5 and 2.

Optional materials which may be employed as the hydrotrope in place ofthe substituted succinic acids are compounds which can form thedicarboxylate ion upon addition to alkaline builder solutions as doessubstituted succinic acid. Such materials, for example, would includemonoor disalts, alkyl esters, amides, and the anhydrides of alkyl oralkenyl succinic acids.

The nonionic surfactant component of the novel blends may be selectedfrom compositions containing a hydrophobic portion and a hydrophilicportion, the latter portion consisting principally or entirely ofpolyethylene oxide units and characterized by the fact that the moleculedoes not ionize in alkaline solutions. Included in these compositionsare ethylene oxide adducts containing amine groups which sometimes areclassed as cationics but actually are nonionics in alkaline solutions,and modified ethylene oxide adducts such as those terminated with benzylgroups and polypropylene oxide chains.

The effectiveness of the above-described hydrotropes in solubilizing thepolyethoxylated nonionic surfactants can readily be demonstrated bycomparing them with a number of prior art solubilizers for nonionics inalkaline builder solutions. In making such comparisons it should be keptin mind that the objective is to provide a solubilizing agent which willallow the highest concentrations of alkaline builders, and which can bepresent at the minimum level for a given amount of nonionic surfactant.Accomplishing this objective is paramount for practical economicconsiderations. Built liquid detergents with low builder levels andconsequently high water contents have excessively high packaging,shipping and handling costs per part of active ingredient. Secondly, itis desirable to have present a minimum amount of any component that doesnot directly contribute to cleaning action; hence the need to keep theamount of hydrotrope present down to the minimum possible consistentwith its required solubilizing activity.

A striking illustration of the effectiveness of the present invention ishad by comparing the solubilizing activity of various substitutedsuccinic acids when blended with the benzyl ether of an ethoxylatedhigher alcohol. This low-foaming nonionics solubility in alkalinebuilder is so poor that, for example, it is not soluble in solutions ofpotassium hydroxide having as little as 5% KOH present. Yet, when thissame nonionic is blended with 80% n-octenyl succinic acid in accordancewith the present invention the blend is soluble in as much as 35% KOHsolutions, as indicated in Table I below which contains data regardingthe solubility of 80/20 blends of potential hydrotropes and the benzylterminated ethoxylate in KOH solution.

In obtaining the data reported in Table I the comparison standardemployed called for a test composi tion to be considered as havingadequate solubility in a system if a clear, homogeneous solution wasobtained over the temperature range of 19-450 C. It will be noted fromTable I that not all of the substituted succinic acid compositions aresatisfactory hydrotropes. Whereas, under the conditions of test thereshown, straight chain alkenyls of 8, 10 and a blend of 7 and 9 carbonatoms, branched chain alkenyls of 9 and 12 carbon atoms and a straightchain alkyl of 8 carbon atoms are effective solubilizers, straight chainalkenyls having 6 carbon atoms are not suitable and neither arecompositions with an alkyl amino group or an aromatic group. The datafurther indicate that an alkyl chain above 12 carbon atoms will not beactive at concentrations of 20% KOH or higher, and therefore would beconsidered unsatisfactory.

Numerous materials besides those listed in Table I were tested,including compositions with previously recognized hydrotropic activityas well as many experimental compositions. None of those materials,other than the substituted succinic acids, gave adequate solubilizationof the nonionic surfactant when subjected to this screening. Theunsatisfactory materials, which includes Na benzene sulfonate, Natoluene sulfonate, Na xylene sulfonate, sodium methyl naphthalenesulfonate, sodium dodecyl diphenylether disulfonate, and n-decvlmonophosphate ester, the results obtained therewith, are reported inTable :11 below. Other compositions found to be ineffective solubilizersinclude Na butyl sulfonate, Na heptyl sulfonate, succinic acid,di-sodium phthalate, di-sodium alpha sulfo octanoic acid, di-sodiumalpha sulfo stearic acid, Na ndecyl monophosphate, Na benzoate, Nanonanoate, and sulfonated naphthalene-formaldehyde condensate.

TABLE I.SOLUBILIZATION OF BENZYL ETHER OF ETHOXYLATED ALCOHOL 1 INALKALINE SOLUTIONS BY VARIO US HYDROTROPES HAVIN G FORMULA- R-CH-CO O11CHz-C O OH Maximum percent KOH in which mate- 1Saialugility p57 rialshows en in -0 solubili l Substttucnt R in acid formula KOH solutioiisemi/ii? Hydrogen 4 20 n-Hexenyl. 20

n-Heptenyl-noncnyl (1/1). 30

n-O ctcnyl E 35 n-Octyl 35 Branched n0ncny1 Clear, 0-45" C... 30

n-Decenyl Clear, 075 C-.- 30

Branched dodcccnyl. Clear, 0-88 C 20 t-Butyl amino Insoluble 3 20 Alphamethyl benzyl Clear, 025 C... 20

Solution contained 5% surfactant, consisting of an /20 ratio ofsubstltuted succinic acid to the nonionic of footnote 1.

3 Insoluble indicates no clear solution from 0-100 0.; mixture scparatesat ambient temperature into two strata.

4 20% was set as an arbitrary floor below which the product wasconsidered inadequate.

5 The di-mcthyl ester, di-sodium salt, di-potassium salt, (Ii-amide, andthe anhydride of n-octenyl succinic acid may be substituted withcssentially the same results.

TABLE II.SOLUBILIZATION OF BENZYL ETHER OF ETHOXYLATED ALCOHOL INALKALINE SOLUTIONS BY VARIOUS HYDROTROPES TABLE II.Coutinued produce aterminal hydroxyl group, an example being an Maximum acetate ester suchas the last nonionic listed in Table III. zffi if TABLEIII.SOLUBILIZATION OF VARIOUS NONIONIG which bllelnd 3 ETHOXYLATES INALKALINE SOLUTIONS l S OW'S solubilizing 5 Solubility of Hydrotrope 2actlvlty Nonionic compositions 2 blend 3 n-CoH1 OE1OHgOO0Na 20t-Oetylphenol Em Clear, 0100 C. n-CaHmOEgGHzGOONB. 20 D0, 1130. 0. OECHgOO ONa 20 Linear primary C12 alcohol Es"- Do. C1215 alkyl amine E15Do. Polydimethyl siloxane-E adduc Clear, 095 0.

Cu acetylenic glycol plus 10 E un Clear, 0- 00H:000H 100 0.

Etllilygznlo )oxide-propylene oxide block copolymer Clear, 0-80 C.

a 28 a Linear primary 010-12 alcohol E4P3 Clear, 059 C. COONa 20 10Linear primary Co-m alcohol E3P3- Clear, 0-46 0. Linear primary 01oalcohol E1001 Clear, 0-54 0. Linear primary C1042 alcohol E4P3 acetateester Clear, 0-59" 0. Na naphthenate 20 Nag phthalate 20 1 5% surfactantinto 20% KOH; surfactant is a 60/40 blend of n-octenyl Na OOCGHeCHCO0Na20 succinic acid/nonionic. Na OOC(CHg)5CO0Na 20 Illustrative of othernonionic surfactant compositions which could Na OOOHQOEQOHZCOONQ, 20 20be blended with he same or other substituted succinic acids, at variousAmino carboxylate hydrotropes: ratios (and naturally with variedperformance), to give an alkali soluble n-C H NHOH2OH2COONa 20 productare: t-oetyl phenol E5, t-octyl phenol E30, hexyl phenol E9,H-CQHZNHOHZOOONB 20 t-octyl phenyl Em t-butyl ether, n-octyloxy E3,oetadecyloxy E12, 012 (CH3)2CHCH2CH(NH2)COON3. 0 amine EaoPno, S80.Cn-qsHza-nOEm ethyl 8.061331, and Sulfonate hydrotropes:

Na benzene sulionate 20 C2H5 Na p-toluene sulfonate.. 20 Na xylenesulionate 20 20 C1u-i2E1oCH2CHO H C HgOE2OHzOHzCHzSOaNa 20 Still othernonionics which are suitable are polyethylene oxide adducts ofOOH2OH2OCH2CH2CH2SO3N& 20 polypropylene oxide where the molecular weightof the propylene oxide chain, and the weight percent of ethylene oxide,are respectively: 1,001 1 1,200 and 40%, 1,501-1,s00 and 20%, 1,5011,800and 80%, 3,200-3,500 and t-C4H NHCH2CH2GH SO3NS. 20 30 30%.

t-OeHmNHOH OH CHzSOaNE. 20 3 N onionics alone are insoluble in 20% KOH.tC8H11NHCH2OH2OH2sO3Na- 20 Nora-E refers to ethylene oxide units, and Prefers to units of Phosphate hy r p propylene oxide.

n-CrHgOEz phosphate 20 zgag E zglgsrgiat Egg The effective ratios ofhydrotrope to IlOlllOIllCS have g g j gg lg g 1 20 been investigated,with the conclusion that any ratio would ResorcinolEz hosphate 39 havesome nonionic solubilizing effect in builder solu- 1CIHEEHO(CH,CH,O),,OH,C5H5 tions, so that the ratio of choice almostbecomes an {:E in certain of the examples of hydrotropes refers toethylene oxide bit Selection Th upper li it f Course, i di d 11111 S.

a 5% oiablend consisting oilpart of C 2-15H25-31O(CH2CH2 )11CH2C5H5 p mp ly y conom1cs. The hy r p portlon, 1t and 4 pa s of the y 40 should benoted, essentially is a diluent since the basic goal Since the data inTable I illustrate the ability of various is to obtain the performanceof the nonionic portion. As substituted succinic acids to solubilize aparticular nona practical matter, a 9/1 ratio is considered to be theefionic in builder solution, it naturally will be of interest fectivemaximum; and the lower effective limit depends to compare data whichillustrate the ability of at least on the nonionic chosen together withthe particular one of the substituted succinic acid hydrotropes tosoluuilder system of interest. Actually, any amount of hybilizg examplesof a number of nonionics under the same 4'0 drotrope added to aIlOIliOIllC Will raise ltS Cl0lld point conditions. Sincepolyethoxylated alcohols are the non- Somewhat; the higher the ratio thegreater the level of ionics of principal interest, due to theirwell-known ulld r whlch can be tolerated. reputation for being among themost effective of all A a l We v found, a m m 0f 1 p r hy roknowndetergents, major types of those ethoxylates were pe t0 3 parts nonionicare needed for solubility at screened i h h results set f rth i T bl 111b l reasonable builder levels. In Table IV, which contains Using a /40ratio (hydrotrope/nonionic) the ethoxdata regarding results obtainedwith different ratios of l t hi h were l bili d i t 20% KOH i l d dsubstituted succinic acid to noniomc, the system chosen adducts ofalkylphenol, higher alkyl (as much as C for llustration resulted inratlos of 9 to 0.33 (25/75) alcohols, alkyl amine, polysiloxane, andalkyl acetylenic Fr p g to be Soluble, a Clear Sohlholl being Obtainedat glycol; other ethoxylated nonionic surfactants include a a least f Inthls System a Tatlo Proved block copolymer of propylene oxide andethylene oxide, to be lnadequately Solubletwo P YP PY olde termmlated h%ethoxylates Table IV.Effect of varying the ratio of substituted and achloro-termmated ethoxy ated alco o succinic acid to nonionic Th data inable III clearl indicate that the effect of th e T 60 Ratio of n-octenylSolubility in 20% e hydrotropes of the present invention is quite ageneral succinic acid at 5% surfactant one for all polyethoxylatenonionics, although it should to IIOIIIOIIICZ KOH solution be understoodthat not all such nonionics will be effective 90/10 Clear 0 100 C underthe conditions described for the examples given 60/40 C1 a 3 C in thattable. Likewise, it should be understood that not 30/70 2; (5 allnonionics are equal with regard to their ease of solu- 25/75 Clearbilization, and the minimum amount of hydrotrope re- 20/80 clear 1quired to effect their solubilization will therefore vary. n

. v u n In general, the nonionic surfactants which will be most Octylpheml E *ethylene Oxlde umts) readily solubilized into builder solutionsby the substituted The solubility of the blends of alkyl or alkenylsuccinic succinic acid hydrotropes of the present invention are acidsand nonionic ethoxylates is, of course, not limited those which have aterminal hydroxyl group. Thus, those to potassium hydroxide solutions.To demonstrate this fact nonionics would certainly be the preferredtypes of surexamples are given in Table V below of several blends infactants. Included in this category would also be comsodiummetasilicate, tetrapotassium pyrophosphate positions which, uponaddition to alkaline builders, would (TKPP) and mixed builder solutions.

TABLE V.-EFFEOTIVENESS OF VARIOUS HYDROTROPES IN VARIOUS ALKALINESOLUTIONS Alkaline builder solutions 2 in which blend is soluble CH3 2Percent alkali in water. 3 5% surfactant. 4 SiO /NazO ratio of 1.86.

Various ones of the blends in Table V have been tested to determinetheir particular utility in a number of use situations. Theseformulations were added to cleaning baths at levels of 1 part offormulation to 50-1000 parts of water. Example No. 5 shows very low foamand effectively removes oils from steel under industrial spray metalcleaning conditions. Example No. 7 exhibits good detergency, low foam,and the ability to defoam proteinaceous food soils in mechanicaldishwashing operations. Example No. 3 is a suitable for use incommercial laundering, particularly with heavily soiled cotton andpolyester-cotton fabrics.

Regarding the methods of preparation of the components of the novelblends described above, it should be noted that any of the manyconventional techniques for preparing the nonionics and the substitutedsuccinic acids may be employed. Preferably, the substituted succinicacids may be prepared by heating a mixture of olefin and maleicanhydride in a closed vessel for a suitable period of time. Thealkenylsuccinic acid anhydride so formed can be purified by distillationor, if a light color is not required and some loss in effectiveness canbe tolerated, the reaction mixture can be used without distillation.Although in some applications the anhydride can be used directly, inothers it is more advantageous to use the acid. Conversion of theanhydride to the acid can be effected by merely contacting the anhydridewith the required amount of Water at elevated temperatures. Otherderivatives of the anhydride, such as esters, amides, salts andsaturated alkyl substituted derivatives can be used but are not asconvenient to formulate and are more expensive to obtain.

From the foregoing specification it will be apparent to those skilled inthe art that the compositions of the present invention are wide in theirscope, both with regard to their formulation and their use, and are notnecessarily limited by the examples hereinabove disclosed.

We claim:

1. A surface active composition consisting essentially of:

(a) 25-90% of a substituted succinic acid,

where R the sole substituent is an alkyl or alkenyl group, branched orstraight chain, of 7 to 12 C atoms, and

(b) -75 of a nonionic polyethoxylated surface active agent.

2. The composition of claim 8 in which the agent is selected from one ofa linear primary C1042 alcohol E 1 a linear primary C alcohol E P alinear primary C alcohol E Cl, a linear primary C alcohol E P acetateester, and ethylene oxide and propylene oxide 8 block copolymer E P Eand E P designation representing ethylene oxide and propylene oxide.

3. The composition of claim 8 in which the nonionic polyethoxylatedsurface active agent is selected from the group consisting of:

R2 R(OH2+O)R R is an alkoxy group whose alkyl portion has 8-18 0 atoms,an alkyl amine Whose alkyl portion has 8-18 C atoms, or an alkyl phenoxygroup Whose alkyl portion has 6 to 12 C atoms,

R is H, a C alkyl group, benzyl, 'acetyl, ethyl acetal, or

chloro group,

R is H, CH or C H and (b) ethylene oxide-propylene oxide blockcopolymers. 4. A surface active composition consisting essentially of ablend containing (a) 25-90% of a substituted succinic acid,

Where where R is an alkyl or alkenyl group, branched or straight chainof 7 to 12 C atoms, and

(b) 10-75% of a low foaming polypropylene oxide terminated ethoxylatedlinear primary alcohol of 8- 12 carbons or the acetate ester thereof.

5. The composition of claim 4 in which the ratio of the substitutedsuccinic acid to the nonionic surfactant is between about 1.5 and 2.

6. The composition of claim 4 in which R is selected from the groupconsisting of n-heptenyl-nonenyl (1/ 1), 'n-octenyl, n-octyl, branchednonenyl, n-decenyl, and branched dodecenyl.

7. The composition of claim 3 in which the nonionic polyethoxylatedsurface active agent is selected from the group. consisting oft-octylphenyl E t-octylphenyl E t-octylphenyl E hexylphenyl Enonylphenyl E dodecylphenyl E t-octylphenyl E t-butyl ether, n-octyloxyE octadecyloxy E C amine E P ethyl acetal, linear secondary alkylalcohol E adduct in which the alkyl group has 11-15 C atoms, linearprimary alkyl alcohol E adduct in which the alkyl group has 12 C atoms,alkyl amine B in which the alkyl group has 12-15 C atoms, polydimethylsiloxane-ethylene oxide adduct, alkyl acetylenic glycol B in which thealkyl group has 14 C atoms, ethylene oxide-propylene oxide blockcopolymers where the propylene oxide block(s) has at least 15 units andthe ethylene oxide block(s) would represent between 10 and Weightpercent of the total, linear primary alkyl alcohol E P in which thealkyl group has 10- 12 C atoms, linear primary alkyl alcohol B' P inwhich the alkyl group has 8-10 C atoms, linear primary alkyl alcohol ECl in which the alkyl group has 10 C atoms, linear primary alkyl E Pacetate ester in which the alkyl group has 10-12 C atoms, the E and Pdesignations respectively representting ethylene oxide and propylenoxide.

8. A surface active composition consisting essentially (a) 25 to of asubstituted alkyl or alkenyl succinic acids of 7-12 carbons selectedfrom the group consisting of the monoand di-sodium and potassium salts,dimethyl esters, and the anhydrides of said acids, which upon additionto alkaline solutions gives the corresponding dicarboxylate ion of saidacids, and

9 10 (b) 10-75% of a nonionic polyethoxylated surface ac- 3,231,5871/1966 Reuse 252-356 tive agent. 3,288,772 11/1966 Becker et a1 252-356References Cited UNITED STATES PATENTS LEON D. ROSDOL, Pnmary Eliiammer2,182,178 12/1939 Pinkernelle 260-326.5F 5 SCHULZ Asslstant Exammel2,283,214 5/1942 Kyrides 252-356 Us Cl XR 2,878,190 3/1959 Dvorkovitz eta1. 252-161 252 356 3,156,655 10/ 1964- Bright 252-89

